Packed into a sardine can of an interview room with about two dozen reporters — most of them sending details of his outing to his home nation of Taiwan — Orioles rookie left-hander Wei-Yin Chen tried to explain the toughest day of his brief major league career.

Through his first seven starts as a big leaguer, the 26-year-old has been close to perfect on paper. He came into Sunday's start against the Washington Nationals with a 4-0 record that included wins over the New York Yankees and Texas Rangers in his past two starts. Sunday presented a new test, facing wunderkind right-hander Stephen Strasburg.

But on Sunday, Chen — whose success can be credited to his mastery of the strike zone — struggled with his location against a fierce Nationals lineup and was outpitched by the 23-year-old Strasburg, leading to the end of the Orioles' nine-game road winning streak in a 9-3 loss in front of an announced crowd of 41,918 at Nationals Park that included large patches of orange.

The only good news to come out of Sunday for the Orioles (27-15) was that the Tampa Bay Rays also lost, so Baltimore maintained its two-game lead atop the American League East standings.

Chen lasted just 41/3 innings, allowing six runs on eight hits — both career highs — while striking out five and walking three. It was the first time he's allowed more than two earned runs in a start and the first time he failed to go at least five innings.

“This is baseball,” Chen said through interpreter Tim Lin. “Sometimes you have a good day; sometimes you have a bad day. Definitely, I had a terrible start today. I couldn't command all my pitches here. And today I was like, ‘Do my job.' But I couldn't do it and I hope I can improve next time.”

Chen had the chance to become just the third Orioles starting pitcher to begin his career 5-0 and just the second rookie to do it, following Ben McDonald in 1990.

But on Sunday, Chen didn't trust his fastball, throwing it less than in any of his previous starts, and he couldn't place his other pitches well when he needed them most.

Chen “got hurt with the breaking ball a lot, and anything off-speed,” Orioles manager Buck Showalter said. “I don't think he gave up a base hit today on a fastball. You pay the price. He made a lot of mistakes with his breaking ball today. That was pretty much the difference.”

With the score tied at 3 in the fourth, the Nationals hit back-to-back homers, with catcher Jesus Flores taking a 2-2 changeup over the high wall in right center-field and Strasburg lining an 0-2 slider into the home bullpen in left field for his first career big league homer.

In the previous inning, Chen hung a full-count curveball to phenom center fielder Bryce Harper that he laced down the right-field line. Nick Markakis nearly caught it, but the ball popped out of his glove for a two-run triple.

“I think he struggled keeping the ball down as the game went on,” said rookie catcher Luis Exposito, who was catching Chen for the first time. “He has great command. I think I might have called too much offspeed in that one inning. As time goes on, you get to start to know these guys and get into sequences with them. Unfortunately, I didn't put down the right fingers today. We had a game plan going in and I just think we didn't execute it the way we wanted to today.”

The Orioles went more than six innings without a hit. Adam Jones' ninth-inning single — which extended his hitting streak to 12 games — was Baltimore's first hit since Xavier Avery singled in a run with two outs in the second. In that span, the Orioles had just one base runner — Exposito, who walked in the seventh.

Most of that could be credited to Strasburg, who settled in after falling behind 3-0 after two innings. He went on to retire the last 10 batters he faced after Avery's single before leaving the game after five innings, allowing just three runs and striking out eight and walking one.

“He used all of his pitches, he threw them for strikes, got ahead of hitters,” Orioles first baseman Chris Davis said. “We did a good job early on getting to him, put some runs on the board and put some pressure on those guys, but they bounced back and he settled down. [He] started staying in the zone a little more, being a little more consistent and was able to hang in there.”

The stingy Nationals bullpen — Paul Gorzelanny (two innings), Tyler Clippard (one) and Ryan Matheus (one) — held the Orioles scoreless for the next four innings.

Ian Desmond's seeing-eye single in the fifth put the Nationals up 6-3 and chased Chen from the game after 92 pitches, his shortest outing of the year. Washington (24-17) tacked on three insurance runs in the eighth off reliever Dana Eveland, highlighted by Danny Espinosa's two-run homer to center field.

After Markakis' RBI single in the first opened the scoring, the Orioles went up 3-0 when Baltimore took advantage of Harper's two-base fielding error in center off the bat of Wilson Betemit to open the second inning. Betemit moved to third on Davis' infield single and scored on a ground out to second. Avery's single to left then scored Davis. It was the Orioles' last hit before the team's offensive drought.

“They've got some really good arms in their bullpen,” Davis said. “It's not like they're bringing up Triple-A guys. They're a good pitching staff.”

The Orioles, who finished their road trip 5-1, loaded the bases in the ninth off Matheus, but pinch hitter Nick Johnson ended the game with a 4-6-3 double play.

“We never quit, all the way to the end,” said Jones, who extended his hitting streak to 12 games with a ninth-inning single. “We got bases loaded, so it shows we still got fight. We're happy. We still won the series, but we're not content because we wanted the sweep.”

Orioles top pitching prospect Dylan Bundy continued his domination of the South Atlantic League on Sunday afternoon with five shutout innings of one-hit ball against the Hagerstown Suns, continuing to fuel talk about whether he's ready to move up to high Class-A ball.